gas leaking from overflow tube

I was given a 1986 vt 500c honda shadow that had not been operated in 20 years. It was left where it was somewhat in the elements. I have never riden and was excited to be getting a bike. I went to a motorcycle driver training course and just received my M Class license. The gas was old when I was given the bike. I emptied the tank, put new gas in and the bike ran like a singer sewing machine. I took the fuel tank and other items off, repaired dents, I did some painting and had a friend paint the tank, fenders etc, had the seat covered and the bike looks great. Tried to start for the first time yesterday and while trying to start it gas was spewing out of what looks like an overflow tube coming off the top of the carbs and down to the bottom of the bike. What went wrong?
Thanks, VaMan

Try tapping firmly (but not Godzilla style) on float bowl which might dislodge a sticking float or crud between float needle and seat.

Overflow often results from imperfect seal between float needle and seat. But might be a float issue, such as sticking or leaking.

Good luck!